1. Field of the Invention
The primer of this invention relates to a primer composition appropriate for adhering curable silicone compositions, particularly heat curable, to the surfaces of various organic materials.
2. Background Information
Silicone rubbers have an excellent heat resistance and for this reason have recently been used in a broad range of applications in which rubber elasticity is required at elevated temperatures. However, silicone rubbers are more expensive than general-purpose synthetic rubbers and general-purpose plastics and have slightly inferior properties, i.e., initial mechanical properties, steam resistance and chemical resistance, etc., compared to some synthetic rubbers and plastics. In order to eliminate these drawbacks of high cost and other unsatisfactory properties, composite materials have been widely used up to now in which the surface of a synthetic rubber or plastic is coated with a silicone rubber so the rubber or plastic material will not suffer from oxidative degradation by oxygen at elevated temperatures.
However, these composite materials occasionally exhibit unsatisfactory capabilities because the silicone rubber does not adhere to the surface of the synthetic rubber or plastic. In particular, silicone rubbers exhibit this drawback with regard to polyolefin synthetic rubbers or plastics. Due to this, the appearance of an effective primer composition would be desirable.
In U.S. Pat. No. 4,332,844, issued June 1, 1982, Hamada et al. teach a silicone composition consisting of an organosilicon compound containing at least one silicon-bonded alkoxy radical per molecule, an organotitanate and an organohydrogen-silicon compound as a primer composition.
In U.S. Pat. No. 4,431,472, issued Feb. 14, 1984, Hohl, et al. teach the use of a primer composition containing (a) a mixture of a silane having an SiC-bonded aliphatic multiple bond and a silane having an SiC-bonded epoxy group and applying a crosslinkable organopolysiloxane composition over the primer.